Thanks Aaron for your input. It seems to me when shooting a longbow I put the pressure of the draw right at the base of my thumb, that is the thumb joint. So, in your practice this would put the center of the bow there. For my hand, this would put the arrow rest about 2" above the center. My original layout would work out about right. Your right, it probably makes little difference, but I in reading one of St. Louis's answers to a letter in P.A., he made a passing reference to the placement. It made me curious as to the theory behind placement.
I never use a shelf on any of my bows. For years, I shot off my knuckle, but for some reason I feel more comfortable with a small leather wedge 1/8-1/4" glued into place for a little placement rest.
Thanks for your comments,
John M. (Dogwood)